Door construction



June 8, 1937. I H. MORRIS 2,083,467

DOOR CONSTRUCTIOI? Filed April 29. 1930 7 Sheets-Sheet l z :33 1 2 43fzz 2c fie Z INVENTOR- BY J? M ATTORNEY Iune 8, 1937. H. MORRIS.2,083,467

DOOR CONSTRUCTION I Filed April 29. 1930 v 7 Sheets-Sheet 2IIIIIIIIIIIIIIIIIIIII.

INVENTOR I M 9 BY 51%. amid;

ATTORNEY June 8, 1937. H. l. MORRIS DOOR consmucnon 7 Sheets-Sheet 5Filed April 29, 1930 INVENTOR JW M Q. 30412;

ATTORNEY June 8, 1937. H. 1. MORRIS DOOR CONSTRUCTION 7 Sheets-Sheet 4Filed April 29, 1930 INVENTOR ATTORNEY June 8, 1937. H. I. MORRIS DOORCONSTRUCTION Filed April 29, 1930 7 Sheets-Sheet 5 ATTORNEY INVENTO June1937. H.-l. MORRIS DOOR CONSTRUCTI ON '7 Sheets-Sheet 6 Filed April 29,1930 INVENTOR V BY Jbwu/ d J1 fly/30M ATTORNEY June 8, 1937. H. 1.MORRIS 2,083,467

- I DOOR CONSTRUCTION Filed April 29, 193O 7 Sheets-Sheet 7 JQAJAJ JQJAfie. 23 {76- 20 INVENTOR ATTORNEY v Patented June 8, 1937 UNITED STATESnoon CONSTRUCTION Howard I. Morris, Lakewood, Ohio, assignor, by

mesne assignments, to Overhead Door Corporation, Hartford City, Ind., acorporation of Indiana Application April 29, 1930, Serial No. 448,377

8 Claims.

This invention relates to a door of the sectional sliding type and thesupporting and operating means therefor.

One object of the invention is to provide a sectional sliding door whichis relatively simple in construction and easily operated.

Another object of the invention is "to provide a sectional sliding doorhaving improved supporting means arranged to facilitate its installationand alignment.

Another object of the invention is to provide an improved mounting forthe rollers between the door sections and the guides, wherebydisalignment due to the position of walls on which the guides aremounted, or bulging and warp-' ing of the guides is fully compensatedfor to the drum carrying shaft.

insure free travel of the door sections.

Another object of the invention is to provide a sectional sliding doorhaving improved counterbalancing means in which the weight of the doorduring vertical travel thereof, prior to the articulation of the doorsections, is compensated for.

Another object of the invention is to construct a sliding door havingimproved guiding and operating means arranged to control the rearmostdoor section, whereby complete closing of the door is insured.

A further object of the invention is to construct a vertically sliding,door having an improved counterbalancing means capable of adjustment,whereby doors of varying sizes and weight may be readily installed.

Another object of the invention is to construct a vertically slidingdoor having improved combined operating and counterbalancing meansserving to slide the door in either direction in a ready manner and withthe exercise of minimum labor.

Other objects of the invention will be apparent to those skilled in theart to which my invention relates from the following description takenin connection with the accompanying drawings,

wherein:

Fig. 1 is a fragmentary view of a structure showing a door openingclosed by a door and operating means therefor embodying my invention;the view being interiorly of the structure and parts being broken away.

Fig. 2 is a fragmentary plan view of the parts shown in Fig. 1.

Fig. 3 is a section on the line 33 of Figs. 1 and 2.

Fig. 4 is a section similar to Fig. 3, but show- ,;5 ing the door inopen position.

Fig. 5 is a section on the line 5-5 of Fig. 1, somewhat enlarged.

Fig. 5a: is a section on the line 5a -5a. of Fig. 1,, somewhat enlarged.

Fig. 6 is a section on the line 6-6 of Fig. 3.

Fig. 7 is a fragmentary elevation of parts shown in Figs. 1 and 3,somewhat enlarged.

Fig. la.- is a fragmentary section similar to Fig. 8 (enlarged), partsbeing omitted. Y Fig. 8 is a section on the line 8-8 of Fig. '7.

Fig. 9 is' a fragmentary side view, similar to Fig. 5, but showing amodified form of construction in which the operating shaft is operatedthrough a reduction gearing.

Fig. 10 is an elevation of parts shown in Fig. 9.

Fig. 11 is a fragmentary elevation on the line ll-Il of Fig. 3, butshowing a modified form of construction.

Fig. 12 is a section on the line l2-|2 of Fig. 11.

Fig. 13 is a view substantially similar to Fig. 5, but showing theapplication of a motor to drive Fig. 14 is a view similar to Fig. 3, butshowing the drum operating shaft mounted in a different position.

Fig. 15 is a view similar to Fig. 14, but showing the door in openposition.

Fig. 16 is a section on the line I6l6 of Fig. 15.

Fig. 17 is a fragmentary view of parts shown in Fig. 14, but showing theapplication of a motor to drive the drum carrying shaft.

Fig. 18 is a view showing a slight modification in which my invention isadapted to an opening the top of which is relatively close to theceiling, the door being shown closed.

Fig. 19 is a view similar to Fig. 18, showing the door open.

Fig. 20 is a bottom plan view of parts shown in Fig. 19, partly insection on the line 2ll--2ll thereof.

Fig. 21 is a view similar to Fig. 18, but showing a further modificationof the invention, the door being shown in closed position.

Fig. 22 is a view similar to Fig. 21, but showing the door in openposition. g

Fig. 23 is a bottom plan view of the parts shown in Fig. 22, partly onthe line 23-23 thereof.

In the drawings, A indicates a building having a door opening B, formedby side members b and a horizontal wall D which may constitute anoverhead beam or lintel, and a ceiling C. These parts are shownconventionally, since they may be variouslyconstructed, moreparticularly the ceiling which may consist of depending cross beams andthe like.

I indicates a door formed of a plurality of sections hingedly orpivotally' connected along their adjoining edges for articulation topermit the door to be guided along guides or tracks 2 having curvedportions intermediate their ends, so that one portion of the guides ortracks may be disposed at an angle to another portion thereof. In theillustrated application of the in.- vention the guides have verticalportions 2a disposed parallel to the side members b, portions zontalportions 20 extending inwardly parallel to the ceiling C. The door Icomprises a lower end section 3, an upper end section 4 and a pluralityof intermediate sections 5, connected in series, preferably by hinges 6to be later described. The number of intermediate sections 5' willdepend upon the length required to close the opening or space Bextending from the floor b" or a sill thereon to the beam -b'. The doorsections may be constructed in any desired manner, for example, of sheetmetal, wood or laminated material, each section preferably havingpanels, certain or all of which may be formed of glass. The sectionsextend across the door opening B and have overlapping relation alongtheir opposite side edges with the side members b as shown in Figs. 2and 6. The articulation of the door sections may be provided for bymeans of a flexible band or chain, but I prefer to use hinges for thispurpose and to utilize the pintles or hinge pins of certain of thehinges in the manner to be later set forth. I provide between theadjoining edges of the door sections a plurality or series of hinges 6,the two outer hinges (designated 6) of each series serving as thesupportportion of each section (except the upper end of the uppersection I) is cut away on its outer face from end to end, as shown at I,and the lower marginal edge portion of each section (except the lowersection 3) is similarly cut away on its inner face from end to end, asshown at 0, these cutaways forming complementary abutting edges havingoverlapping portions arranged to seal the joints between the sectionswhen the door is closed. As will be understood, the hinge pins for thehinges 6, 6, are in line with the joints between the side walls of thecutaways l and the upper free ends of the lower sections, respectively.

The guides 2 are disposed in parallel relation to each other in planesbeyond the opposite sides b of the door opening B and in spaced relationto the inner faces of the side members b and ceiling C. Each guide 2 maybe and preferably 7 portion 20, and a bracket ll suitably secured- I tothe wall A and supporting the curved portion 211. While each guide maybe formed from a single section or length of material, I prefer to makethe portions 20, 2c, in separate sections and to mount between them acasting shaped or fashioned to provide the curved guide portion 2b andthe bracket l I. In the forms of construction shown the curved guideportion 217 registers with the adjacent ends of the guide portions 2aand 20 to form a continuous guide. As shown, the ends of the castings iiare shaped to permit the adjacent ends of the guide portions 2a, 20, totelescope into such ends to align with the curved portion 2b. This formof construction is advantageous as it eliminates all curving of theguides and permits the guide sections 241, 20, to be cut from stock ofthe exact length required without waste. The castings ll may also form asupport for parts of an operating means l2 (to be later described) andit insures between parts of the operating means l2.and the door guides afixed. relation, which is not affected by relative movement betweenportions of the building A due to sagging or settling of its foundation.

Each hinge 6 preferably comprises a pair of plates 6b suitably securedto the inner faces of adjoining door sections, the inner end of oneplate being rolled into a knuckle l3 and fitting between struck-up endportions It on the opposite sides of the inner end of the other plateand a pin extending through the knuckle l3 and openings formed in theend portions ll, the ends of the pin being headed over in a well knownmanner. Each hinge 6 is preferably of similar construction, except thatits hinge pin I! is (a) provided with a collar i6 engaging the outer endportion H to prevent endwise movement inwardly of the hinge pin and (b)its outer end is extended to form a shaft I1 on which loosely floats aroller 6a (already referred to), while running in the adjacent guide 2.Each roller to may be of the anti-friction type, preferably comprisingan inner element I8 rotatably and slidably engaging the shaft l1, anouter element Ita having rolling engagement with the adjacent guide andinterposed balls l9, which roll in the races provided on the opposedwalls of the elements ll, Ila, and also look these elements ,againstendwise movement one relative to the other. Each guide section comprisesa base portion 20 secured/to the adjacent angle 9 (see Fig. 6) or hangerll, diverging portions 2| and opposed roller engaging portions 22, andone of the latter portions is provided along its inner edge with aninturned wall 23, which co-operates with the adjacent portion 2| toguide therolier la along or in line with ,the track portions 22. Byforming the guides as above described, the rollers 0a are prevented frommoving laterally relative to the roller engaging or track portions 22 asthe door slides from one position to the other; but due to the fact thatthe rollers rotatably and slidably fit upon the shafts H, the rollersare free to accommodate themselves to the position of the guides, due to(a) variations in the spacing of the guides, so that great care is notrequired, in installing the latter, to space them to any great degree ofaccuracy, (b) bulging of the respective guide sections between theirends and (c) disalignment of the guides due to sagging of the structuralmembers of the structure or relative movement thereof incident tosettling ta are normally arranged midway of the shaft l1, so that therollers may slide laterally thereon in either direction. This form ofconstruction also permits the door to float relative to the rollers dueto (a) contraction or expansion of parts of the door operating means and(b) warping of the door sections. By providing the guides with thediverging portions 2|, 2|, ample room is provided for endwise movementof the shafts IT, in the event the rollers 60, guided by the guides 2,slide inwardly.

The rollers 62: at the lower end of the section 3 are mounted on shaftssupported by brackets 24 threaded on the bolt 36 and arranged to engage(see Fig. '7), the latter being secured to plates 24a, which will belater described.

Of the operating means I2, 25 indicates a shaft having journal bearingsupport at its opposite ends in suitable hangers 26 preferably formedintegrally with and extending inwardly from the casings II to supportthe shaft inwardly of the door I when closed. One end of the shaft isextended and provided with a driving element, such element in Figs. 1,2, 3, 4 and 5, comprising a sprocket 21, around which a chain loop 28travels, the sprocket being fixed to the shaft 25 and the loop dependingdownwardly, whereby pull on eitherleg of the loopmay be effected torotate the sprocket and shaft in the desired direction to open or closethe door.

Where it is found desirable to operate the shaft 25.through reductiongearing, the shaft is provided with a gear 28' that meshes with a pinion29, the shaft for the latter being mounted on the adjacent hanger 26 andhaving the sprocket 21 secured to it. This form of driving means isshown in Figs. 9 and 10.

Also, where it is found desirable to apply power to rotate the shaft 25,I mount a reversible electric motor 29 on one of the hangers and connectto the motor shaft a worm 30, which meshes with a worm gear 3|, fixed tothe shaft 25, a suitable switch (not shown) being provided to controlthe supply of current to the motor. This form of construction is shownin- Fig. 13.

32, 32, indicate drums fixed to the shaft 25 and arranged near theopposite side edges of the door sections, but preferably thereof. Thedrums are preferably formed with spiral grooves to guide cables 33, 33,as they wind on and off the drums. The upper ends of the cables 33 aresuitably secured to the inner ends of the drums and extend from thelatter to the lower end of the lower door section 3, to which end thecables are secured in the manner to be later set forth. The drums have adiameter proportioned to their length to permit winding of the completelength of the cable thereon when the door slides from its closedposition (Figs. 1,

I2 and 3) to its full open position (Fig. 4). In this arrangement, theshaft may be mounted approximately in or slightly above the plane of thetop b, or adjacent the upper end of the guide section 2a.

Each cable is connected to the lower end of the lower door section 3 bythe following instrumentalities: 34 indicates a plate secured to theinner face of the door section adjacent its side edge. The plate 34 isprovided with an outwardly extending member 34a. having an elongatedopening 35 formed in its outer portion. 35 indicates a hollow boltextending through the opening 35, the head of the bolt being formed witha conical recess communicating with the opening through the bolt. Theadjacent cable extends through the bolt and its free end is suitablyanchored in the recess in the bolt head. 31 indicates a nut theunderside of the member 34a to'secure the bolt and cable thereto. Bypreference the undersides of the member 34a at opposite sides of theopening 35 are convexed to permit the nut 31 to rock without unduefriction to accommodate 0 the bolt 35 to the direction of pull on theadinwardly position, whereby it may be raised and lowered in arectilinear direction and parallel to the guides 2. As the cables aredisposed on the inner side of the door and connected to the inner faceof the door section, they may be readily connected and disconnected aswell as adjusted. A suitable nut 31' may be utilized to loci; the nut 31in adjusted position.

38 indicates a counterbalancing means for the door arranged tocompensate for the weight thereof when in closed position and toproportionately decrease as the sections successively move from theguide portion 2a to the guide portion 2c; and likewise toproportionately increase in the closing movement of the dooras thesections successively move from the guide portion 20 to the guideportion 2a. In the construction herein provided, I use a spring 39 whichmay be adjusted to provide a predetermined tension depending upon theweight of the door and also adjusted to provide for a predeterminednumber of turns of the spring end that is fixed to the shaft 25 as thedoor I moves from one position to the other, depending upon the lengthof travel of the lower door section 3. By reason of such dual adjustmentI may use for all installations a spring of sufficient length and sizeto provide for doors of different weight (maximum weight or less) anddoors of different height (maximum height or less) and thus avoidcarrying in stock a large assortment of springs. The spring 39 is coiledaround the shaft 25 and one end of the spring is anchored to a collar 40adjustably secured to the shaft 25. The other end portion of the springis held against turning by a device 4| which carries an arm 42 engaginga cross member 43, the latter being secured to the brackets II andserving to brace them. The device 4| comprises a pair of blocks Ma, Ma,engaging op posite sides of the spring 39 and rigidly clamped togetherand to the spring by a plurality of bolts 44. By adjusting the device 4|longitudinally of the spring 39, the effective length thereof isincreased or diminished, so that in the rotation of the shaft 25 withthe drums 32 as the door I moves from full open position to full closedposition, that end of the spring fixed to the shaft may turn therewithand generate tension in the spring proportionate to the increase inweight of the door as its sections progressively move from the guidesection 20 to the guide section 2a, to the end that when the door iscompletelyaclose-d sufiicient tension will have been imparted to thespring tosubstantially counterbalance the weight of the door. As thespring tension increases proportionately to the increase in weight ofthe door in its closing movement, the tension of the spring decreasesproportionately in the opening movement of the door as the weightthereof decreases due to its upper sections progressively sliding alongthe guides to the horizontal position. In this arrangement it Will beseen that the spring operates to counterbalance at all times only thatportion of the door which is in the guide portion 2a, so that verylittle manual or motor power movably receive the arm 42. By rotating thedevice M, the spring may be placed under an initial tension.

In the form of construction shown in Figs. 1 to 10, inclusive, the lowerends of the curved guide sections are relatively close to but slightlyabove the top wall b, so that in the opening movement of the door theupper end section 4 slides from the vertical toward the horizontalimmediately as such movement takes place and effects a correspondinglydecrease in the weight of the door. Where the arrangement andconstruction of the building A is such that the guide sections 2a extendvertically, to a point above the top b so that the entire door slidesvertically before its upper section traverses the curved portions ID, Iprovide drums of special construction to compensate for this preliminaryvertical travel so that the counterbalancing effect or tension of thespring 39 on the door will be uniform throughout such travel as well asthe remaining travel of the door sections to the full open position.Referring to Figs. 11 and 12 I show a drum 32' for .one of the cables, asimilar drum (not shown) being provided at the other end of the shaft 25for the other cable. The drum 32' is tapered, as shown at Ma, from itsinner end to its body portion 32b, this tapered portion being soproportioned as to its length and inclination or angularity with respectto its body portion that the cable wlnds'thereon during the preliminaryvertical travel of the door and then winds on the body portion 321;during its remaining travel to the full open position. By reason of thetapered portions 32a, it will be seen that while in or during thepreliminary upwardly travel of the door the spring tension is beingreduced, the counterbalancing eifect upon the door or upward pull on thecables 33 will remain uniform. In the vertical travel of the door in itsclosing movement the same uniform tension effect will result due to theunwinding of the cables from the tapered portions 32a.

In Figs. 14, 15 and 16 I show a slightly different form of constructionwherein the supporting brackets, indicated at 36' are arranged at oradjacent the upper end of the curved guide section 26, being formedintegrally with the castings II and connected by a cross piece 43.Asshown, these brackets support the shaft 25 so that the drums 32 arearranged relatively close to the ceiling. This form of construction isadvantageous where the space above the top I) of the door opening isrestricted. Y

Fig. 1'? shows a form of construction in which a reversible electricmotor 43 is used to drive the shaft 25. In this arrangement, the motor43 is mounted on a base 41 which is suitably secured to the adjacentbracket 23", and the motor shaft is connected to a shaft 43, alsomounted on the base 41 and carrying a worm 43, which meshes with a wormgear 50 suitably fixed to the shaft 25.

Where the top b of the door opening B is relatively closeto the ceilingC, as shown in Figs 18, 19, 21 and 22, it will be noted that the curvedguide section 2b merges into the vertical guide section 2a at a pointbelow the top b and as a result the upper portion of the upper doorsection would not be guided into closing relation with the top b as itis in Figs. 1, 2, 3, 4 and 5, in the closing movement of the door. 'Toprovide for the movement of the upper end of the door section 4 intoclosing position, I provide auxiliary supporting means therefor soconstructed and mounted and connected to such door section end toyieldingly stop the doors.

that the latter is moved into closed position when the door slidesdownwardly to the limit of its movement (see Figs. 18 and 21) and ismoved in the opposite direction and supported in the plane of theremaining door sections when the door slides to its open position. Theauxiliary supporting means comprise a pair ofcarriers I, each pivoted attheir inner ends to the upper end of the section by a hinge Ha,preferably similar to the hinges 3 already described. Each carriercomprises a plate 82 disposed at the inner side of and parallel to theadjacent guide and slidably mounted on the latter, by a pair of rollers53, one arranged adjacent the outer end of the plate 53 and the otherroller arranged intermediate the ends of the plate, both rollers beingmounted on shafts 54 carried by fixed supports 55. In this arrangementof the rollers 53, the inner ends 32a of the plates 52 project inwardlybeyond the inner roller, so that as the rollers 53 traverse the curvedguide section 2b, the ends 520, which, being hingedly connected to theupper end of the door section I, will carry the latter in a path beyondthe curved guides 2b and into the position shown in Fig. 18, therebypositioning the door section 4 in the plane of the remaining doorsections and against the wall A above the top b.

Where it is found that in the open position the weight of the lower doorsection 3 is not suiilcient to permit ready movement of the door to ortowards its closed position, Imay provide a pair of supplemental cables63 (see Figs. 21, 22 and 23) between the drums and the upper end portionof the door or the outer ends of the carriers, as

' shown, these cables being adapted to wind on and on the drums 33. Inthis arrangement, the carriers are made somewhat longer so that theouter ends of the carriers will be rearward of the cable drums when thedoor is closed, and the rollers therefor-spaced a greater distance andthe extended supporting end 52a proportioned so as to guide the upperend of the door section into closing position-see Fig. 21. Accordingly,when the shaft .35 is rotated, the cables 56 will wind on the drums (asthe cables 33 unwind therefrom) and exert a pull on the door to slide italong the guides. I interpose in each cable 36 a spring 51 to compensatefor the non-uniform movement of the supporting rollers in traversing thecurved guide sections 2b.

53 indicates means for yieldingly stopping the door at its upper limitof movement. Such means may be applied to the forms of constructionshown in Figs 1 to 1'7, inclusive, although I have only shown. itapplied to the forms shown in Figs. 18 to 23, inclusive. The form ofmeans shown comprises devices which guide the cables to and fromthedrums and is so arranged that it causes the spring tension tobetexerted 'in a direction which relieves pull on the door section ,3.Each device 53 consists of a plate having a groove through which theadjacent cable extends and an outwardly extending guide portion Ila thedevice being arranged near the upper portion of the section 3 so thatwhen the latter reaches the position shown in Figs. 19, 20, 22 and 23,the spring tension is relieved and whatever tension is exerted suchtension is exerted at an angle to the door, the effect of which is bethrust upwardly with suillcient force to. move the devices beyond theshaft 25, the tension of the counterbalancing spring will yieldinglyarrest the door, as well as serve to return them to its normal openposition.

To prevent breakage I may also provide positive stops 59 at the outerend of each guide portion 20, these stops comprising pins whichsecuresuch section to the adjacent hanger.

To those skilled in the art to which my invention relates many changesin construction and widely differing embodiments and applications of myinvention will suggest themselves without departing from the spirit andscope of the invention. My disclosures and the description herein arepurely illustrative and are. not intended to be in any sense limiting.

-What I claim is:

1. In a door construction, the combination of a pair of spaced guidescomprising vertical portions related to a door openingland portionsdisposed at an angle to the vertical portions, a door comprisingconnected sections articulatable to traverse said guides, rollerscarried by the door sections and engaging said guides, an elevated shaftdisposed between the ends of said guides and between and inwardly ofsaid portions thereof, drums on said shaft disposed inwardly of the sideedges of said door sections, flexible members extending from said drumsand connected to the inner face of one of the door sections, and meansfor rotating said shaft. v

2. In a door construction, the combination of a pair of spaced guidescomprising vertical por tions related to a door opening and portionsdisposed at an angle to the vertical portions, a door comprisingconnected sections articulatable to traverse said guides, rollerscarried by the door sections and engaging said guides, an elevated shaftdisposed between the endsof said guides and between and inwardly of saidportions the're of, drums on said shaft disposed inwardly of the sideedges of said door sections, flexible members extending from said drumsand connected to the inner face of the lower door section adjacent itslower edge, and means for rotating said shaft.

3. In a door construction, the combination of a pair. of spaced guidescomprising vertical portions related to a door opening and portionsdisposed at an angle to said vertical portions, a door comprisingconnected sections articulatable to traverse said guides, devicescarried by said door sections and engaging said guides to slidablysupport said sections thereon, a shaft supported adjacent the top of thedoor opening between said guide portions, a drum secured to said shaft,a flexible member arranged to wind on and off said drum and connected tothe lower portion of the lower door section, a fiexible member arrangedto wind on and off said drum and operatively connected to the outerportion of the upper door section, and means for operating said shaft.

4. In a door construction, the combination of a pair of spaced guidescomprising vertical portions related to a door opening and portionsdisposed at an angle to said vertical portions, a door comprisingconnected sections articulatable to traverse said guides, devicescarried by said door sections and engaging said guides to slidablysupport said sections thereon, a shaft supported adjacent the top of thedoor opening between said guide portions, a drum secured to said shaft,a flexible member arranged to wind on and off said drum and connected tothe lower portion of the lower door section, a flexible member arrangedto wind on and off said drum and operatively connected to the outerportion of the upper door section, and means for operating said shaft,the connectiombetween the last mentioned flexible member and the upperdoor section including an expansion spring.

5. In a door construction, the combination of a pair of spaced guidescomprising vertical portions related to a door opening and portionsdisposed at an angle to the vertical portions, a door comprisingconnected sections articulat able to traverse said guides,rollers'carried by the door sections and engaging said guides, an

elevated shaft disposed between the ends of said guides and inwardly ofand between said portions thereof, a drum on said shaft, a flexiblemember extending'from said drum and connected to the lower door section,a spring coiled around said shaft and fixed thereto at one end, and arelatively fixed connection for the opposite end of the spring, saidconnection being adjustable longitudinally of the spring.

6. In a door construction, the combination of a pair of spaced guidescomprising vertical portions related to a door opening and portionsdisposed at an angle to the vertical portions, 2. door comprisingconnected sections articulatable to traverse said guides, rollerscarried by the door sections and engaging said guides, an elevated shaftdisposed between the ends of said guides, a drum on said shaft, aflexible member extending from said drum and connected to the lower doorsection, a spring coiled around said shaft and connected thereto at oneend, and a relatively fixed connection for the opposite end of saidspring, the effective length of said spring being variable.

7. In a door construction, the combination of a pair of spaced guidescomprising vertical portions related to a door opening and portionsdisposed at an angle to the vertical portions, a door comprisingconnected sections articulatable to traverse said guides, rollerscarried by the door sections and engaging said guides, an elevated shaftdisposed between the ends of said guides, a drum on said shaft, aflexible member extending from said drum and connected to the lower doorsection, a spring coiled around said shaft and connected thereto at oneend, and a relatively fixed connection for the opposite end of saidspring, the effective length of said spring being variable, and one ofsaid connections being adjustable to affect the tension of said spring.

8. In a door construction, the combination of a pair of spaced guidescomprising vertical portions related to a door opening and portionsdisposed at an angle to the vertical portions, a door comprisingconnected sections articulatable to traverse said guides, rollerscarried by the door sections and engaging said guides, an elevated shaftdisposed between the ends of said guides, drums on said shaft disposedinwardly of the side edges of said door sections, flexible membersextending from said drums and connected at their outer ends to thelowermost door HOWARD I. MORRIS.

